Adding annual MRI to annual mammography screening cost $69,125 for each additional QALY gained. Although there is no consensus in the U.S. on what constitutes a cost-effective intervention, commonly cited threshold values range from $50,000 to $100,000 per QALY, according to Dr. Lee.

Annual combined screening was best at detecting early stage cancers and provided the greatest relative mortality reduction. Combined screening became more cost-effective as breast cancer risk increased, and less cost-effective as risk decreased.

MRI screening was associated with an increase in false-positive results. Annual mammography resulted in 37 false-positive screening examinations for every breast cancer death averted. The addition of annual MRI increased the number of false-positive results to 137 for each breast cancer death averted.

"The benefits provided by MRI are balanced by an increased chance of needing additional tests to evaluate a possible abnormality, and perhaps even a biopsy that might in the end show no cancer," Dr. Lee said.

Source: Radiological Society of North America